[vsnet-grb-info 9203] GRB100425A: Swift/UVOT Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  10689
SUBJECT: GRB100425A: Swift/UVOT Upper Limits
DATE:    10/04/25 18:00:55 GMT
FROM:    Samantha Oates at MSSL  <sro at mssl.ucl.ac.uk>

S. R. Oates (MSSL-UCL) and D. Grupe (PSU) report on behalf of the  
Swift/UVOT team:

The Swift/UVOT began settled observations of the field of
GRB 100425A 88s after the BAT trigger (Grupe et al., GCN 10673).
We do not detect a new source at the enhanced Swift XRT position
(Goad et al. GCN 10686) and at the location of source B detected
by the VLT telescope (Malesani  et al. GCN 10680) and GROND
telescope (Olivares et al. GCN 10683). Photometry is complicated
by the prescence of the VLT source A within the source aperture.

The 3-sigma upper limits for the finding chart exposures (FC)
and summed images are:

Filter   T_start   T_stop   Exp(s)  Mag (3-sigma upper limit)
-------------------------------------------------------------
white (FC)  88      238      147         >19.37
white       88      5778     513         >19.59
u     (FC)  301     551      246         >18.92
u	    301     6796     650         >19.08
v           631     11961    1317        >19.76
b           556     5573     236         >19.71
uvw1        680     6600     432         >19.44
uvm2        4757    12580    997         >20.87
uvw2        606     11048    1318        >21.26
-------------------------------------------------------------

The quoted upper limits have not been corrected for the expected
Galactic extinction along the line of sight of E_(B-V) = 0.15 mag.
All photometry is on the UVOT photometric system described in Poole et
al. (2008, MNRAS, 383, 627).